Probe needle, method for manufacturing the probe needle and method for constructing a three-dimensional structure

ABSTRACT

A method for manufacturing a probe needle having beams and a contactor placed on tips of the beams comprises preparing a Si wafer  20 , forming a seed layer  21  on the Si wafer  20 , and forming grooves in a desired shape of the beams on the seed layer  21  by patterning a photoresist  23 . Subsequently, the grooves are filled up with metal-plated layers  24   a,    24   b  to form the desired shape of beams.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/661,349, filed Feb. 28, 2007, now U.S. Pat. No. 7,619,424 whichclaims the benefit of priority to Japanese Patent Application Nos.PCT/JP05/15637, filed Aug. 29, 2005, and JP2004-251081, filed Aug. 30,2004. The entire contents of both of these applications are incorporatedherein by reference.

TECHNICAL FIELD

This invention relates to probe needles, a method for manufacturing thesame and a method for constructing a three-dimensional structure, andmore particularly, to a complex shape of probe needle, a method formanufacturing the same and a method for constructing a three-dimensionalstructure.

BACKGROUND ART

Conventional probe needles are described in U.S. Pat. No. 6,255,126 andU.S. Application No. 2003/0113990, for example.

U.S. Pat. No. 6,255,126 discloses a spring contactable probe needleformed by successively depositing a plurality of layers.

In addition, U.S. Application No. 2003/0113990 discloses a probe needlewith a cantilevered-beam supported by a plurality of legs and a methodfor manufacturing the same.

Conventional probe needles are thus manufactured and structured asdisclosed in the above publications. According to U.S. Pat. No.6,255,126, the probe needle is fixed at its base part and is formed bysuccessively depositing a plurality of layers so that the probe needlezigzags but extends generally straight upwardly. When a contactor formedon the tip of this probe needle makes contact with an object to betested, the beam part may bend and hit the adjoining beams, causingbreakage of the beams. Similarly, U.S. Application No. 2003/0113990discloses the same basic configuration. Therefore, it is impossible todensely arrange the probe needles and to form the desired shape of probeneedles. Even if it is possible, the manufacturing method of such probeneedle could be complicated.

DISCLOSURE OF THE INVENTION

The present invention is made in view of the problems and has an objectto provide a probe needle that can be densely arranged and have anydesired shape, a method for readily manufacturing the probe needle and amethod for constructing a three-dimensional structure.

A probe needle according to the present invention includes a pluralityof serpentine beams fixed at one of their ends and a connecting sectionplaced at the other ends of the plurality of serpentine beams and forconnecting with the plurality of serpentine beams. The connectingsection is provided with a contactor on its one side that is opposite tothe side to which the beams are connected.

Preferably, the plurality of serpentine beams are a pair of beams thatare folded at a predetermined frequency, and the folding frequencies ofthe pair of the serpentine beams are the same.

More preferably, the pair of serpentine beams are mutually out of phase.

More preferably, the mutual folding phase shift between the pair ofserpentine beams is 180 degrees.

One end of the probe needle is preferably connected to an interposer.

In another aspect of the present invention, a method for manufacturing aprobe needle having long beams and a contactor placed at tips of thebeams includes a step of preparing a substrate, a step of forming a filmhaving grooves in the shape of the beams on the substrate, a step offorming metal layers inside the grooves, and a step of removing thesubstrate and film to take out the metal layers.

Preferably, the grooves in the shape of the beams are in a serpentinepattern.

More preferably, the serpentine pattern includes a first serpentinepattern and a second serpentine pattern located away from the firstserpentine pattern.

It is preferable that the first and second serpentine patterns havefolded curves at a predetermined frequency.

A positioning groove for each of the first and second serpentine groovesmay be formed concurrently with the formation of the first and secondserpentine grooves.

Preferably, the method for manufacturing the probe needle furthercomprises a step of separating the film having the first serpentinegroove and the film having the second serpentine groove from thesubstrate having the first and second serpentine grooves, a step ofaligning the separated films having the first serpentine groove and theseparated films having the second serpentine groove with respect to thepositioning grooves, and a step of bonding the aligned films with abonding material.

The bonding material used herein is preferably an interlayer insulationfilm. In addition, the interlayer insulation film is made of an organicresin material.

More preferably, the method for manufacturing the probe needle furthercomprises a step of fixing the base portions of the beams. The step offixing the base portions of the beams includes a step of preparing abeam retaining member having fixing sections to which the base portionsof the beams are fixed. The beam retaining member has a plurality offixing sections each having a connection hole that is wider on the frontside and becomes inwardly narrower. The step of fixing the base portionsof the beams includes a step of removing a part of the films bonded withthe bonding material from the base portion side of the beams to exposethe base portions, made of the metal layers, of the beams as anchorpiles, and a step of inserting the exposed anchor piles into theconnection holes.

The beam retaining member is preferably an interposer.

Preferably, the method for manufacturing the probe needle furthercomprises a step of connecting the beams made of the metal layers in thefirst and second serpentine patterns and the contactor.

In another aspect of the present invention, a method for constructing athree-dimensional structure comprises a first step of preparing asubstrate, a second step of forming a film having grooves in a desiredcomplex shape on the substrate, a third step of forming metal layersinside the grooves, and a step of removing the substrate and film totake out the metal layers, thereby constructing the desired complexthree-dimensional structure with the metal layers.

Preferably, the method for constructing the three-dimensional structurefurther comprises a step of preparing a plurality of substrates havinggrooves with the metal layers formed therein by repeating the first tothird steps, a step of aligning the prepared plurality of substrateshaving the grooves with the metal layers formed therein, and a step ofremoving the aligned plurality of substrates and films to take out themetal layers.

More preferably, the step of aligning the prepared plurality ofsubstrates having the grooves with the metal layers formed thereinfurther includes a fourth step of forming positioning holes forpositioning, a step for preparing a plurality of substrates having thepositioning holes and grooves with the metal layers formed therein byrepeating the first to fourth steps, and a step of aligning the preparedplurality of substrate having the grooves with the metal layers formedtherein with respect to the positioning holes.

The probe needle according to the present invention includes a pluralityof serpentine beams each having one fixed end and the other endconnected to the connecting section that is provided with the contactor.The two serpentine beams supporting a contactor bend with a certainbending strength along the only direction in which the curved portionsof the serpentine beams exist.

By limiting the bending direction of the beams, the probe needle can bearranged densely.

In addition, the probe needle according to the present invention canobtain a desired bending strength by adjusting the folding frequency ofthe serpentine beams.

In another aspect of the present invention, a method for manufacturing aprobe needle having long beams and a contactor placed at tips of thebeams includes a step of preparing a substrate, a step of forming a filmhaving grooves in the shape of the beams on the substrate, a step offorming metal layers inside the grooves, and a step of removing thesubstrate and film to take out the metal layers.

The beam sections of the probe needle can be formed by forming grooveson a plane substrate, and therefore any complex shaped beam can bereadily formed.

As a result, a method for readily manufacturing any shape of probeneedles can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of probe needles according to oneembodiment of the invention.

FIG. 2A is a plan view of a substrate in the course of a manufacturingmethod of beams of the probe needle.

FIG. 2B is a cross-sectional view taken along line B-B of FIG. 2A.

FIG. 3A is a plan view of a wafer in the course of the manufacturingmethod of the beams of the probe needle.

FIG. 3B is a cross-sectional view taken along line B-B of FIG. 3A.

FIG. 4A is a plan view of the wafer in the course of the manufacturingmethod of the beams of the probe needle.

FIG. 4B is a cross-sectional view taken along line B-B of FIG. 4A.

FIG. 4C is a plan view of a photoresist layer.

FIGS. 5A-5C illustrate a method for making up a plurality of probebeams.

FIG. 6 specifically illustrates the beams of FIG. 5 in a bonded state.

FIG. 7 illustrates steps of the manufacturing method of the beam of theprobe needle.

FIGS. 8A-8B illustrate the plurality of beams of the probe needle bondedtogether.

FIGS. 9A-9E illustrate a method of attaching the probe needles to aninterposer in another embodiment.

FIG. 10 illustrates another example of the probe needle shape accordingto the invention.

DETAILED DESCRIPTION OF THE INVENTION

By referring to drawings, description will be made regarding oneembodiment of the invention below. FIG. 1 is a perspective view of probeneedles according to one embodiment of the invention. With reference toFIG. 1, a probe needle 10 includes two serpentine beams 14 a, 14 b fixedat one of their ends (base portions) on a block 15, a connecting section12 connecting the other ends of the two serpentine beams 14 a, 14 b, anda contactor 11 placed on the connecting section 12 to contact an objectto be tested.

In FIG. 1, two probe needles 10 are mounted on the block 15.

In this embodiment, each of the two serpentine beams 14 a, 14 b arefolded at a predetermined frequency (interval) so that the curved partsof the beams 14 a, 14 b are 180 degrees out of phase with each other inthe height direction, in other words, the convex curves of the beam 14 aalign with the concave curves of the beam 14 b, and accordingly the beam14 a pairs up with the beam 14 b.

Because the probe needle 10 is thus cantilevered with the pair ofserpentine beams 14, which are 180 degrees out of phase with each other,from the block 15, the probe needle 10 bends only in the direction alongthe curved parts of the beams 14 (i.e. direction indicated by X of FIG.1). Consequently, this configuration limits the bending direction of theprobe needle, therefore enabling a dense arrangement of the plurality ofprobe needles 10.

Alternatively, the pair of serpentine beams 14 a, 14 b can have thecurved parts being in phase with each other. Such beams 14 a, 14 b canmake the probe needle 10 more bendable in a certain direction. Byadjusting the phase shift of the pair of serpentine beams 14 a, 14 b,adjustment of the bending strength of the beam can be made.

This serpentine beam is not limited to such a shape including the curvedparts and linear parts as shown in FIG. 1, but may be corrugated orzigzagged.

In addition, description is made regarding the two probe needles 10mounted on one block 15 with reference to FIG. 1, the present inventionis not limited to this. The block 15 can receive one probe needle, threeprobe needles, or more. This block 15 may be anything as long as theprobe needle 10 can be fixed on; however, preferably is an interposer aswill be described later.

Next, description will be made regarding a method for manufacturing theprobe needle 10. FIGS. 2 through 7 illustrate the respective steps ofthe manufacturing method of the probe needle 10 according to oneembodiment of the invention.

FIG. 2A is a plan view, and FIG. 2B is a cross-sectional view takenalong line B-B of FIG. 2A (FIGS. 3 and 4 below are shown in an analogousfashion). Referring to FIG. 2, a Si wafer 20 is first prepared as asubstrate, and a seed layer (e.g. Au layer) 21 is formed on a surface ofthe Si wafer 20.

Next, as shown in FIG. 3, the desired shape of grooves, which will bebeams of a probe needle, are formed on the seed layer 21 with the use ofa photoresist 23 for example. In FIG. 3, resist pattern is formed on onepiece of Si (SiO₂ or SiN) wafer 20 so as to expose a pair of serpentinegrooves 25 a, 25 b, which are symmetrically curved with respect to acenter line (hereinafter referred to as “out of phase”), four matingsides 27 and a center line 28 surrounding the pair of serpentine grooves25 a, 25 b, and mating holes (grooves) 26.

The mating sides 27 and mating holes 26 are used for positioning as willbe described later.

Because the part to be the beams of the probe needle 10 can be thusformed on the Si wafer 20 in a two-dimensional manner, any shape of thebeam can be formed.

At the time of forming the beams, the positions of base portions 17 a,17 b, which are fixed on the block 15, and the positions of free ends 18a, 18 b, which are connected to the connecting section 12, of the pairof serpentine grooves 25 a, 25 b can be accurately determined byphotolithography.

Next, as shown in FIGS. 4A and 4B, serpentine-shaped plated layers (e.g.Au layers) 24 a, 24 b are formed on the pair of serpentine grooves 25 a,25 b, respectively.

Subsequently, the exposed parts of the seed layer 21, that is, the fourmating sides 27 and center line 28 surrounding the pair of serpentineplated layers 24 a, 24 b are melted, for example, to be removed togetherwith the substrate on which the seed layer is formed. Then, as shown inFIG. 4C, photoresist layers 31 each having a serpentine plated layer 24and mating hole 26 are taken out. FIG. 4C shows only the left part ofFIG. 4A.

FIGS. 5A-5C show a method for making up a plurality of probe needlepairs with the photoresist layers 31, which are taken out in FIG. 4C andhave the mutually out-of-phase plated layer 24 a or 24 b.

FIG. 5A illustrates the photoresist layers 31, each of which having themutually out-of-phase serpentine plated layer 24 a or 24 b, successivelyaligned in contact with each other; FIG. 5B illustrates a plurality ofconnecting sections 12, each of which having a contactor 11 thereon,connected to the free ends 18 of the serpentine plated layers 24 a, 24 bformed in the photoresist layers 31; and FIG. 5C illustrates aconnection face of a silicon interposer 40 having a plurality of fixingsections 41 at which the base portions 17 of the serpentine platedlayers are fixed. The connecting sections 12 in FIG. 5C are representedas if they have no thickness, however they actually have a predeterminedthickness as shown in FIG. 1.

It should be appreciated that the photoresist layers 31 having theserpentine plated layers 24 a, 24 b and also the serpentine platedlayers 24 a, 24 b have a predetermined depth, however, FIGS. 5 and 7just illustrate the photoresist layers 31 in solid lines and the platedlayers 24 a, 24 b in thick lines for the sake of clarity.

The separated photoresist layers 31 as shown in FIG. 4C are positionedwith respect to the mating holes 26 as shown in FIG. 5A. The positionedstate of the photoresist layers 31 are shown in FIG. 6. In FIG. 6, fourphotoresist layers 31 a to 31 d are positioned.

In addition, the plurality of photoresist layers 31 can be positionedwith respect to the above-mentioned precisely formed mating sides 27instead of the mating holes 26.

Referring to FIG. 6, the photoresist layers 31 a to 31 d are temporarilybonded with a bonding material 33 placed therebetween. The bondingmaterial 33 used herein is preferably an interlayer insulation film. Theinterlayer insulation film can be made of an organic resin material suchas electrodeposited polyimide. The reason why the organic resin materialsuch as electrodeposited polyimide is used is that the materials'resilient property facilitates positioning as will be described later.

A connecting section 12 is mounted on every pair of free ends 18 of thethus bonded photoresist layers 31. The connecting section 12 is made ofAu for example, and forms a metal junction for connection with theserpentine-shaped plated layer 24 which is also made of Au.

At this point, if the plurality of connecting sections 12 are initiallyformed as one piece as shown in FIG. 5B and then placed on the free ends18 of the plurality of photoresist layers 31, easier connection betweenthe connecting sections 12 and the free ends 18 of the photoresistlayers 31 can be achieved.

As shown in FIG. 5C, the base portions 17 of the photoresist layers 31are connected to the fixing sections 41 of the silicon interposer 40 inthe same manner. The fixing sections 41 used herein are also made of Aufor example, and form a metal junction with the respective base portions17 of the photoresist layer 31.

After the free ends 18 and base portions 17 of the photoresist layers 31are connected with the connecting sections 12 and fixing sections 41 ofthe silicon interposer 40, respectively, as shown in FIGS. 5 and 6, theSi wafer 20 and photoresist layer 31 are melted to be removed asillustrated in FIG. 7.

As shown in FIG. 7, with the removal of the photoresist 23, a pluralityof probe needles 10 can be obtained each having a pair of Au serpentinebeams 35 a, 35 b, which are mutually out of phase with each other, andin which the base portions 17 are connected to the fixing sections 41 ofthe silicon interposer 40 and the free ends 18 are connected to theconnecting section 12.

It should be understood that the photoresist 23 is used in thisembodiment and therefore melted to be removed; however a resin resistand metal resist are also available and the removal thereof may bechosen depending on the resist material in use. For example, ashingtechnique with oxidation can be also effective instead of the meltingtechnique.

Another embodiment of the present invention will be described now.

FIG. 8 illustrates another embodiment of the invention. The descriptionwith reference to FIGS. 5 to 7 is for the case where there is no specialproblem in alignment of the serpentine beams 35 and the fixing sections41 provided on the silicon interposer 40.

However, the positions of the serpentine beams 35 and fixing sections 41do not always match well. In view of this problem, next description willbe made regarding the case of misalignment of the serpentine beams 35and fixing sections 41 in this embodiment.

FIG. 8A corresponds to FIG. 4C in the last embodiment, while FIG. 8Billustrates a plurality of photoresist layers bonded together shown inFIG. 8A viewed from the bottom.

FIG. 8A shows the photoresist layers 51 each including two serpentineplated layers formed therein. Thus, the plurality of photoresist layers51 each having the plurality of beams can be bonded as shown in FIG. 6.

Referring to FIG. 8A, the photoresist layer 51 in this embodimentchanges according to the thickness of the photoresist 23 at the time offormation. For example, as shown in FIG. 8B, the pitch between thebonded photoresist layers is d1. In this case, the base portions 17 ofthe serpentine beams 35 are formed at pitch d1, but the pitch d1 maygenerally vary by plus or minus 5 μm depending of the dimension of thephotoresist 23 at the time of formation.

On the other hand, the fixing sections 41, which are connected with thebase portions 17, on a surface of the silicon interposer 40 are formedat a constant interval (e.g. d2). Because photolithography is used toform the pair of serpentine beams 35 on the photoresist layer 51, thedimension d3 between base portions 17 a and 17 b can be positioned withconsiderably high precision.

As apparent from FIGS. 8A and 8B, the dimension d1 between the baseportions in the thickness direction of the photoresist layer 51 does notalways match with the corresponding interval between the fixing sections41 on the silicon interposer 40.

FIGS. 9A to 9E show the process subjected to the photoresist layer 51and silicon interposer 40 in order to deal the mismatch. FIG. 9Aillustrates the photoresist layer 51 in FIG. 8A with the beams aroundtheir base portions. FIG. 9B illustrates the photoresist layer 51 withanchor piles 37 made of the plated layer 24 by etching a given quantityof the photoresist layer 51 in the state shown in FIG. 9A from the baseportion side of the beams. FIG. 9C illustrates the silicon interposer 40with pyramid windows 42, serving as the fixing sections 41, formed onits surface.

FIG. 9D is a view on arrow IX in FIG. 8A. The lower part of FIG. 9Dillustrates the anchor piles 37 exposed by removing the photoresist 23as shown in FIG. 9B. FIG. 9E is a cross-sectional view taken along lineE-E of FIG. 9C. On the front surface of the silicon interposer 40,wiring layers 46 are formed which are connected to wiring layers 48 onthe rear surface of the silicon interposer 40 via through holes 47.

The illustrations of FIGS. 9A to 9E are made with reference to the caseof FIG. 8 as an example, however the process can be applied to the caseof FIG. 6 in an analogous manner.

Note that the drawings in FIGS. 8A, 8B and FIGS. 9A to 9E, illustratingthe serpentine beams 35 in the direction including the curved surfaceare represented in an enlarged manner, and the number of the serpentinebeams 35 does not coincide with the number of the fixing sections 41formed on a front face of the silicon interposer 40.

Next, description will be made regarding a method for connecting theanchor piles 37 formed at the base portions 17 of the serpentine beams35 and the fixing section 41 on the silicon interposer 40. Thephotoresist layer 51 in the state of FIG. 9A is etched to partiallyremove the photoresist 23 enclosed by the dotted line and to expose thebase portions 17 of the plated layer 24 as shown in FIG. 9B, therebyforming the anchor piles 37.

On the other hand, pyramid windows 42 are formed with insulating filmsat the fixing sections 41 so as to have wider openings at the frontsurface of the silicon interposer 40 and to be inwardly narrower. Asshown in FIGS. 9D and 9E, even if the pitch d1 between the anchor piles37 a and 37 b is different from the pitch d2 between the pyramid windows42 a and 42 b, the anchor piles 37 a, 37 b can be inserted into thepyramid windows 42 a, 42 b as shown by heavy arrows in FIG. 9E becausethe bonding material 33 such as electrodeposited polyimide havingresilient property is stretchable in the direction indicated by arrowsas shown in FIG. 9D, thereby enabling secure connection of theserpentine beams 35 and the fixing sections 41 on the silicon interposer40.

Although each of the pyramid windows 42 a, 42 b in this embodiment has arectangle opening on the front surface of the silicon interposer 40 andfour sides inwardly inclined from the opening, the pyramid windows 42 a,42 b are not limited to the above shape and can have two oppositetapered sides or one tapered side. In addition, when the anchor piles 37are cylindrical, conical windows are also available.

Yet another embodiment of the present invention will be now described.FIG. 10 illustrates yet another embodiment of the invention. Referringto FIG. 10, complex shaped beams 50 used in probe needles are formed atthe fixing sections 41 on the silicon interposer 40 in this embodiment.Since photolithography is used to form the beams of the probe needleswith a resist in this embodiment, any complicated shape of beam 50 inuse for the probe needle can be formed as shown in FIG. 10.

The description in this embodiment is about the formation of any complexshape of beams in use for the probe needle, however, the presentinvention is applicable to the method for constructing any complexthree-dimensional structure as shown in FIG. 10 by the method describedin FIGS. 2 to 9.

The “complex shape” in this embodiment includes at least shapes thatcannot be expressed by a single line.

In the above mentioned embodiments, photoresist and photolithography areused to form the desired shape of beams, the present invention is notlimited to this, and any film can be utilized to form the beams as longas the film allows the grooves, which will be the beams of the probeneedle, to be formed thereon.

Although the probe needles are connected to the silicon interposer inthe above-mentioned embodiment, the present invention is not limited tothis and applicable to interposers made of any kind of material.

Although the metal layers to be the beams of the probe needles areplated in the above mentioned embodiment, the present invention is notlimited to this, and the metal layers can be formed by any method.

Although the plated layers are made of Au in the above mentionedembodiment, the present invention is not limited to this, and any kindof metal is available for the plated layers.

Although Au is used for the connecting section with the contactor andthe connecting section with the interposer in the above mentionedembodiment, the present invention is not limited to this, and any kindof metal is available for the connecting sections.

Although the free ends and fixed ends of the plated layers form metaljunctions for connecting with the connecting sections in the abovementioned embodiment, an appropriate connection method can be adoptedaccording to the material to be connected.

The foregoing has described the embodiments of the present invention byreferring to the drawings. However the invention should not be limitedto the illustrated embodiments. It should be appreciated that variousmodifications and changes can be made to the illustrated embodimentswithin the scope of the appended claims and their equivalents.

INDUSTRIAL APPLICABILITY

The probe needle according to the present invention including beamsections formed in plane can take on any complex shape and therefore canbe advantageously utilized.

1. A method for manufacturing a probe needle having long beams and acontactor disposed at tips of the beams, the method comprising the stepsof: preparing a substrate; forming a film having grooves in the shape ofsaid beams on said substrate; forming metal layers inside said grooves;and removing said substrate and said film to take out said metal layers,wherein said grooves in the shape of said beams are in a serpentinepattern, wherein said serpentine pattern includes a first serpentinepattern and a second serpentine pattern located away from said firstserpentine pattern, and wherein said first and second serpentinepatterns have folded curves at a predetermined frequency.
 2. The methodfor manufacturing the probe needle according to claim 1, furthercomprising a step of forming a positioning groove for each of saidgrooves in said first and second serpentine patterns concurrently withthe formation of said grooves in said first and second serpentinepatterns.
 3. The method for manufacturing the probe needle according toclaim 2, further comprising the steps of: separating the film having agroove in said first serpentine pattern and the film having a groove insaid second serpentine pattern from the substrate having said grooves insaid first and second serpentine patterns; aligning said separated filmshaving said groove in said first serpentine pattern and said separatedfilms having said groove in said second serpentine pattern with respectto said positioning grooves; and bonding said aligned films with abonding material.
 4. The method for manufacturing the probe needleaccording to claim 3, wherein said bonding material is an interlayerinsulation film.
 5. The method for manufacturing the probe needleaccording to claim 4, wherein said interlayer insulation film is made ofan organic resin material.
 6. The method for manufacturing the probeneedle according to claim 3, further comprising a step of fixing baseportions of the beams, the step of fixing said base portions of thebeams comprising the steps of: preparing a beam retaining member havingfixing sections to which said base portions of the beams are fixed,wherein said beam retaining member has a plurality of fixing portions,and each of said plurality of fixing portions of the beam retainingmember has a connection hole being wider on the front side and becominginwardly narrower; removing a part of said aligned films bonded with thebonding material from the base portion side of the beams to expose thebase portions, made of said metal layers, of the beams as anchor piles;and inserting said exposed anchor piles into said connection holes. 7.The method for manufacturing the probe needle according to claim 6,wherein said beam retaining member is an interposer.
 8. The method formanufacturing the probe needle according to claim 1, further comprisinga step of connecting said beams made of the metal layers in said firstand second serpentine patterns and said contactor.